"BIL stands for “Breeding. Impromptu.
Luminary.” [BIL] is an ad-hoc conference for big thinkers that’s held each
year in whatever city is hosting TED. BIL originally began as a group
of people planning to crash the TED conference in 2007 in Monterey,
California (where TED was held back then), but as the group grew, they
decided instead to hold their own unconference across the street.

BIL is a conference style more than it is a
conference. Like Barcamp, anyone can organize and hold their own BIL
conference. So BIL conferences are popping up all over the world as
places “for passionate people to come together to energize, brainstorm,
and take action.”

The whole "un-conference" concept is one to watch. Not sure there's any proof for this, but I'm wondering if the naming of BIL was a clever reference to "BIL and TED's Excellent Adventure"? If so, BIL looks like a most excellent adventure.